Incidence Of Postoperative Myocardial Infarction Research Articles

Effect of β-blocker Prescription on the Incidence of Postoperative Myocardial Infarction after Hip and Knee Arthroplasty

American College of Cardiology/American Heart Association guidelines recommend beta-blockade for selected low- and intermediate-risk noncardiac surgery patients. The authors evaluated the effect of perioperative beta-blockade on postoperative myocardial infarction (POMI) in low-risk patients undergoing intermediate-risk surgery. Patients who underwent elective hip or knee arthroplasty between January 1, 2002 and June 30, 2006 were identified. POMI was defined as a Troponin T value of more than 0.1 ng . ml(-1). Patients were divided into three groups: those prescribed a beta-blocker on the day of surgery and throughout their hospital stay (or 7 days, whichever came first), those prescribed a beta-blocker on the day of surgery but discontinued during the first 7 days, and those not prescribed a beta-blocker on the day of surgery. Propensity analysis and logistic regression were used to determine the independent association of beta-blocker exposure on POMI. Of the 5,158 arthroplasty patients, 992 (18%) were treated with beta-blockers on the day of surgery. This beta-blocker was discontinued in 252 patients (25%). POMI occurred in 77 patients (1.5%). Discontinuation of beta-blocker prescription was significantly associated with POMI (odds ratio 2.0; 95% CI 1.1-3.9) and death (odds ratio 2.0; 95% CI 1.0-3.9). After adjustment for confounders, discontinuation of beta-blocker prescription during the first week after surgery was significantly associated with POMI and death. These findings confirm the American College of Cardiology/American Heart Association Guidelines on Perioperative Cardiovascular Evaluation and Care for Noncardiac Surgery, which recommend not to withdraw beta-blocker therapy.

Heparin-Coated Stents Do Not Protect Cancer Patients from Cardiac Complications after Noncardiac Surgery

Previous studies regarding preoperative coronary stents and antithrombotic agents have excluded patients with cancer as a result of hypercoagulability. The objective of this study is to determine whether preoperative heparin-coated coronary stents are as safe in patients with cancer undergoing surgery as patients without cancer. Between February 2003 and February 2005, 29 patients had heparin-coated coronary stents placed before noncardiac surgery. The incidence of postoperative myocardial infarction (MI) and/or death was compared in patients with and without cancer, and outcomes were further evaluated based on preoperative antithrombotic status. Postoperative MI occurred in three of 13 (23%) patients with cancer compared with zero of 16 noncancer patients. Patients with cancer were 9.6 times more likely to have a postoperative MI resulting in death compared with noncancer patients. There was a positive correlation between patients having cancer and having a postoperative MI (r = 0.38, P = 0.044) and between patients with cancer being on antithrombotic medications during surgery and having a postoperative MI (r = 0.567, P = 0.044). After stent placement, patients with cancer undergoing surgery experienced a higher incidence of postoperative MI resulting in death compared with noncancer patients despite continued antithrombotic use. In these patients, alternatives to stenting should be considered to avoid perioperative cardiac complications.

Factors affecting post minimally invasive direct coronary artery bypass grafting incidence of myocardial infarction, percutaneous transluminal coronary angioplasty, coronary artery bypass grafting and mortality of cardiac origin

In the present study we identify parameters which influence the incidence of myocardial infarction (MI), need for percutaneous coronary intervention (PCI), coronary artery bypass grafting (CABG) and cardiac mortality after minimal invasive coronary artery bypass grafting (MIDCABG). With a mean follow-up of 30+/-11.2 months, 390 patients were assessed with Wald test-corrected chi(2) analysis to identify preoperative factors which correlate with a higher incidence of post-MIDCABG MI, PCI, CABG and mortality from cardiac causes. We found an increased incidence of postoperative MI in patients with 2-vessel (8.7%) and 3-vessel (7.7%) vs. 1.3% 1-vessel coronary artery disease (CAD) (P=0.023), and in patients with preceding cardiac procedure (CABG and PCI: 8.4% vs. 2.0% without, P=0.023). Also diabetes was associated with higher post-MIDCABG frequency of MI (P=0.035). Severity of angina was associated with lesser post-MIDCAB-PCI (P=0.011) while preceding CABG predicted a higher incidence (P=0.012). Preoperative low ejection fraction (EF) (multivariate, P<0.001), preoperative MI (P=0.007) and extent of CAD (P=0.001) were associated with a higher post-MIDCABG mortality. None of the parameters correlated with subsequent CABG MIDCABG. The extent and history of CAD, history of cardiac interventions and low EF seem to influence the outcome adversely and should be considered deciding pro or against the MIDCAB-option.

Does Tight Heart Rate Control Improve Beta-Blocker Efficacy? An Updated Analysis of the Noncardiac Surgical Randomized Trials

Recent meta-analyses assessing the efficacy of perioperative beta-blockade trials have failed to show a reduction in postoperative morbidity and mortality. Tight control of heart rate (HR) has been suggested to improve these outcomes. Meta-analyses have not considered the influence of tight HR control on the efficacy of perioperative beta-blockade. Using previously published search strategies, we identified all randomized trials evaluating perioperative beta-blockers after noncardiac surgery. This search yielded 10 trials with 2176 patients. We used the data from these studies to correlate measures of HR control with major postoperative outcomes, primarily in-hospital myocardial infarction (MI). Odds ratio (OR) and 95% confidence intervals (CI) were calculated, and metaregression was performed correlating measures of HR control with MI. The combined results of all studies did not show a significant cardioprotective effect of beta-blockers, with considerable heterogeneity among the studies (OR = 0.76; 95% CI = 0.4-1.4; P = 0.38 heterogeneity: I(2) = 34%). However, grouping the trials on the basis of maximal HR showed that trials where the estimated maximal HR was <100 bpm were associated with cardioprotection (OR = 0.23; 95% CI = 0.08-0.65; P = 0.005) whereas trials where the estimated maximal HR was >100 bpm did not demonstrate cardioprotection (OR = 1.17; 95% CI = 0.79-1.80; P = 0.43) with no heterogeneity. Moreover, metaregression of the HR response to beta-blockade against the log OR of postoperative MI demonstrated a linear association between the effect of beta-blockade on the mean, maximal, and variation in HR and the OR of an MI (r(2) = 0.63; P < 0.001) where a larger effect of beta-blockers on HR was associated with a decreased incidence of postoperative MI. Across all studies, beta-blockade resulted in a reduction in postoperative HR (weighted mean difference: 8.6 bpm; 95% CI = -9.6 to -7.6; I(2) = 85.3%) with considerable heterogeneity. This large heterogeneity in HR response to beta-blockade was found to be related, in part, to the type of beta-blocker, specifically, metoprolol, and the concomitant use of calcium channel blockers. Calcium channel blocker use and beta-blockers other than metoprolol resulted in more effective control of HR. There was wide variability in the HR response to beta-blockade. Twenty-five percent of patients receiving beta-blockers had episodes when the HRs were more than 100 bpm, although 15% of placebo patients also had bradycardia, which would have required a dose reduction had they been administered beta-blockers. Finally, this analysis found that perioperative beta-blockade was associated with an increased incidence of bradycardia (OR = 3.49; 95% CI = 2.4-5.9) and congestive heart failure (OR = 1.68; 95% CI = 1.00-2.8). The trials that achieve the most effective control of HR are associated with a reduced incidence of postoperative MI, suggesting that effective control of HR is important for achieving cardioprotection. Second, this analysis demonstrates that administration of beta-blockers does not reliably decrease HRs in all patients, and may be associated with increased side effects. Judicious use of combination therapy with other drugs may be necessary to achieve effective postoperative control of HR.

Myocardial infarction and cerebrovascular accident following non-cardiac surgery: differences in postoperative temporal distribution and risk factors.

Myocardial infarction and stroke after non-cardiac surgery are two ominous cardiovascular complications believed to share similar pathophysiological processes. However, the differences in the temporal distribution between them have not been adequately investigated in a large cohort of patients. The preoperative clinical features and daily occurrence of myocardial infarction and stroke were routinely recorded in 36 634 consecutive patients following elective non-cardiac, non-carotid surgery. The preoperative characteristics and postoperative daily distribution of postoperative myocardial infarction and stroke were compared using exponential and linear regressions models. Myocardial infarction and stroke occurred in 122 (0.33%) and 126 (0.34%) patients, respectively, during the first 30 days after surgery. More patients with myocardial infarction had diabetes mellitus and cardiac disease (P = 0.041 and <0.0001, respectively) whereas more patients with stroke were older and female (P = 0.003 and 0.038, respectively). The peak incidence of myocardial infarction was on the day of surgery (43%) and declined exponentially thereafter (F = 725.4, P < 0.0001). However, postoperative stroke best fitted a linear regression with almost even daily distribution (F = 15.9, P = 0.0004). The median time to myocardial infarction was one day [95% confidence interval (95% CI) = 0-2 days] compared with nine days (95% CI = 7-11 days) for stroke. The peak incidence of postoperative myocardial infarction is early after non-cardiac surgery and declines exponentially thereafter, as opposed to stroke, which occurs at a constant rate during the postoperative period. Myocardial infarction and cerebrovascular accident following non-cardiac surgery differ in their preoperative risk factors, and in the postoperative time-line of their occurrence.

The One Year Incidence of Postoperative Myocardial Infarction in an Orthopedic Population

The diagnosis of a postoperative myocardial infarction (PMI) is important in the orthopedic population because these events can be associated with significant cardiac morbidity. Plasma troponin I (cTnI) analysis has markedly increased our ability to detect myocardial damage. Using cTnI analysis for evidence of a PMI, we prospectively assessed all of our patients for (1) the 1-year incidence of PMI, (2) the clinical consequences of a PMI in relation to the level of the cTnI release, and (3) 6-month follow-up for cardiac complications. During a 12-month period, patients at risk for perioperative myocardial ischemia were assessed for a PMI by serum cTnI levels and daily serial ECGs. Patients with cTnI levels above the reference level (> or = 0.4 ng/ml) were also assessed for new cardiac regional wall motion abnormalities with an echocardiogram and 6-month postdischarge adverse cardiac events. Of the 758 patients who were assessed for a PMI, 49 patients had detectable cTnI levels (> or = 0.4 ng/ml); the incidence of a PMI was 0.6% of all surgical cases and 6.5% of those patients were at risk for a cardiac event. A PMI was more common after hip arthroplasty than other orthopedic procedures. Twenty-three patients had a cTnI level >3.0 ng/ml, and 74% these patients (17/23) had anginal symptoms and/or ischemic ECG changes. Nine of these patients (9/23) had new postoperative echocardiographic changes, five (5/23) required emergency transfer to a cardiac care unit, and 10 (10/23) had postoperative cardiac complications. In contrast, 15 patients with levels of cTnI <3.0 ng/ml and without ischemic ECG changes and/or anginal symptoms had no postoperative cardiac complications. Fourteen patients (14/47) had cardiac complications 6 months after discharge, including four cardiac deaths, one fatal stroke, and four patients with unstable anginal episodes that required a change in medical management, and six patients required coronary revascularization. Orthopedic surgical patients with cTnI level <3 ng/ml and without symptoms or ECG changes suggestive of myocardial ischemia (15/49) may have different risks than those with higher-level cTn1.

The MBL2 ‘LYQA Secretor’ Haplotype Is an Independent Predictor of Postoperative Myocardial Infarction in Whites Undergoing Coronary Artery Bypass Graft Surgery

Mannose-binding lectin (MBL) is an important component of innate immunity and activator of the lectin complement pathway. Within the MBL2 gene are seven 5' "secretor" haplotypes that code for altered serum MBL levels and complement activation. However, recent evidence suggests that 3' MBL2 haplotypes may also modify MBL function and circulating levels. Because MBL and the lectin complement pathway have been implicated in cardiovascular injury, we investigated whether MBL2 haplotypes are independently associated with an increased risk of postoperative myocardial infarction (PMI) in patients undergoing coronary artery bypass graft surgery. Genotyping of 18 polymorphic sites within the MBL2 gene was performed in a prospective, longitudinal multi-institutional study of 978 patients undergoing primary coronary artery bypass graft-only surgery with cardiopulmonary bypass between August 2001 and May 2005. After adjustment for multiple comparisons by permutation testing, multivariate, stepwise logistic regression, including a score test, was performed controlling for patient demographics, preoperative risk factors, medications, and intraoperative variables to determine if MBL2 secretor haplotypes are independent predictors of PMI in whites undergoing primary coronary artery bypass graft surgery. Neither the 5' nor 3' MBL2 haplotypes alone were associated with an increased incidence of PMI. However, the incidence of PMI in whites (n=843) expressing the combined MBL2 5' LYQA secretor haplotype (CGTCGG) and 3' haplotype (CGGGT) was significantly higher than in whites not expressing the haplotype (38% versus 10%; P<0.007). Moreover, the combined MBL2 LYQA secretor haplotype was an independent predictor of PMI in whites after primary coronary artery bypass graft surgery after adjustment for other covariates (P<0.02; adjusted OR: 3.97; 95% CI: 1.30 to 12.07). The combined MBL2 LYQA secretor haplotype in whites was also an independent predictor of postoperative CKMB levels exceeding 60 ng/mL (P<0.02; adjusted OR: 4.48; 95% CI: 1.95 to 16.80). Inclusion of the combined MBL2 LYQA secretor haplotype improved prediction models for PMI based on traditional risk factors alone (C-statistic 0.715 versus 0.705). The combined MBL2 LYQA secretor haplotype is a novel independent predictor of PMI and may aid in preoperative risk stratification of whites undergoing primary coronary artery bypass graft surgery.

The Influence of Propofol Versus Sevoflurane Anesthesia on Outcome in 10,535 Cardiac Surgical Procedures

The purpose of this study was to evaluate the possible cardioprotective effect of sevoflurane versus propofol anesthesia in patients undergoing cardiac surgery. Ten thousand five hundred thirty-five consecutive single cardiac surgical procedures from 3 cardiac centers were reported to a common registry from 1999 to 2005. The registry was established by the National Board of Health, and reporting was obligatory for all public heart centers in Denmark. The patients were stratified according to preoperative risk factors (EuroSCORE parameters). The outcome parameters were 30-day mortality, the incidence of postoperative myocardial infarction, and the incidence of postoperative arrhythmias. Overall, the 30-day mortality was lower after sevoflurane (2.84%) versus propofol (3.30%), although not significantly so (p = 0.18). No difference was found in the incidence of postoperative myocardial infarction (sevoflurane, 7.76%/propofol, 7.47%). Patients with preoperative unstable angina and/or recent myocardial infarction, and thus already "preconditioned," did not show any difference in mortality between anesthetic groups, whereas patients without these predictors showed a lower postoperative mortality after sevoflurane (2.28% v 3.14%, p = 0.015), which can at least partly be explained by a preconditioning-like effect. The data suggest that patients suffering relatively severe preoperative ischemic stress benefited from propofol anesthesia, which can be related to the antioxidant effects of propofol. Patients in the sevoflurane group had a higher incidence of postoperative atrial fibrillation (28.75% v 24.87%, p < 0.001), whereas patients in the propofol group showed a higher incidence of all other arrhythmias. Sevoflurane and propofol both possess some, although different, cardioprotective properties. Sevoflurane appears to be superior to propofol in patients with little or no ischemic heart disease, such as noncoronary artery bypass graft (CABG) surgery and CABG surgery without severe preoperative ischemia, whereas propofol seems superior in patients with severe ischemia, cardiovascular instability, or in acute/urgent surgery.

Incidence of postoperative myocardial infarction in non cardiovascular surgery

Incidence of postoperative myocardial infarction in non cardiovascular surgery

Myocardial protection by nicorandil during open-heart surgery under cardiopulmonary bypass

To evaluate the myocardial protective effect of nicorandil when used as an adjuvant to cold hyperkalaemic cardioplegia in open-heart surgery. Patients who underwent surgery under cardiopulmonary bypass (CPB) for mitral valve replacement (MVR, 23 patients) or coronary artery bypass grafting (CABG, 24 patients) were entered in a double-blind study. The patients were randomized to a nicorandil Group (N) or placebo Group (P). Nicorandil 0.1 mg kg-1 (Group N), or normal saline (Group P), were administered at three time points: (1) after aortic cannulation, but prior to going on CPB, (2) 5 min before aortic cross-clamping and (3) 5 min before reperfusion. The following variables were studied: (a) time until electromechanical arrest after cardioplegia administration (Tarrest), (b) time until return of electromechanical activity after aortic cross-clamp removal (Trecovery), (c) incidence of postoperative myocardial infarction or low output syndromes (d) dysrhythmias requiring intervention after aortic cross-clamp removal and (e) haemodynamic changes after nicorandil administration. The Tarrest after cardioplegia administration was significantly faster in nicorandil group in both MVR and CABG patients (P 75 IU L-1 in MVR patients was significantly lower in the Group N than in placebo patients (P < 0.05). However, in CABG patients there was no such significant difference. The incidence of dysrhythmias requiring intervention after aortic cross-clamp removal was also less in Group N. Administration of 0.1 mg kg-1 boluses of nicorandil did not cause significant haemodynamic changes or precipitate dysrhythmias in any patient. Nicorandil enhances the myocardial protective effect of cold hyperkalaemic cardioplegia in cardiac surgery patients.

Double Supply to Left Anterior Descending Artery by Additional Saphenous Vein Graft in Internal Thoracic Artery Malperfusion Syndrome

Internal thoracic artery (ITA) grafting to the left anterior descending artery (LAD) may have catastrophic consequences and can be fatal due to "ITA malperfusion syndrome." We have investigated the efficacy of a second graft in this syndrome. A total of 35 patients, 29 males (82.9%) and 6 females (17.1%), with a mean age of 53.0 +/- 8.7, (range: 38 to 70) undergoing coronary artery bypass grafting required a second supply to LAD due to ITA malperfusion syndrome. This was performed using a saphenous vein graft. The mean number of distal anastomosis was 2.7 +/- 0.45 per patient (range: 1 to 5). The decision for an additional grafting procedure was made in the first operation for 18 patients (51.4%) (Group I). For the remaining 17 patients (48.6%) (Group II), the additional grafting procedures were performed during a reoperation after the development of ischemic complications in the intensive care unit (ICU). The early mortality rate was 8.6% (3 of 35). Two patients had perioperative myocardial infarction (MI) (5.7%). The second vein graft proved to dramatically reduce the incidence of postoperative MI. Malignant refractory arrhythmias were recorded in 17 patients (48.6%). Twelve patients (34.3%) required inotropic support and seven patients (20%), all in Group II, required intra-aortic balloon pump (IABP) support. The average duration of IABP was 5 days +/- 1.8 days (range: 3 to 7). The necessity of IABP support was found to be statistically higher in the second group compared to the first one. Double supply to LAD using an additional saphenous vein graft is the treatment of choice for ITA malperfusion syndrome. The time interval between the first and the second grafts appears to be crucial for postoperative patient outcome.

Coronary artery surgery: conventional coronary artery bypass grafting versus off-pump coronary artery bypass grafting

Coronary revascularization has become the principal treatment modality in patients with severe coronary artery disease. The broader application of percutaneous coronary interventions in patients with multivessel disease and the recent introduction of drug-eluting stents have both lead to a decline in the number of patients referred for surgical revascularization. Conventional coronary artery bypass grafting using cardiopulmonary bypass is an excellent treatment, however less invasive surgical approaches such as off-pump coronary artery bypass grafting have appeared in the past few years. The exact role of off-pump coronary artery bypass grafting is still vaguely defined and being critically evaluated. Our aim is to provide an objective review of the recent literature in regard to surgical outcomes. A critical review of all relevant clinical series from May 2003 to May 2005 was conducted. Current prospective data suggests that both techniques have similar rates of mortality, in regard to morbidity, multiple prospective studies suggest a decrease in stroke rates for off-pump coronary artery bypass grafting. The incidence of postoperative myocardial infarction does not appear to differ between techniques. When analyzed carefully, the results presented herein seem to indicate that both techniques provide similar rates for long-term patency and freedom from surgical reintervention. Coronary artery bypass grafting and off-pump coronary artery bypass grafting are both safe and beneficial in patients with multivessel coronary artery disease. It appears that elderly patients with additional co-morbid risk factors may benefit most from off-pump coronary artery bypass grafting. It has become increasingly apparent that off-pump coronary artery bypass grafting can be performed safely in reference centers.

Skeletonization of the radial artery with the ultrasonic scalpel: clinical and angiographic results.

To improve the patency rate of the radial artery graft, we have been using a skeletonized harvesting technique since September 1, 2001. Our early reports confirmed better graft patency of the skeletonized radial graft than the conventional pedicled graft. However, its midterm results were unknown. We present our recent experience and follow-up results of radial artery grafting using the skeletonized harvesting technique. Between September 1, 2001, and July 31, 2002, 391 patients underwent isolated coronary artery bypass surgery in our hospital group, excluding minimally invasive direct coronary bypass procedures via small thoracotomy or T-grafting. Among them, skeletonized radial grafting was performed in 246 patients (182 men and 64 women; mean age, 66.2 +/- 9.5 years). Follow-up is to be completed by December 31, 2003. Perioperative, early angiographic, and follow-up results were analyzed. There were 1 hospital death and 5 incidences of postoperative myocardial infarction. None of these occurrences were related to radial artery bypass. Early angiography revealed that the stenosis-free graft patency rate of radial artery anastomoses (291/303 cases, 96.0%) was not significantly different from the patency rates of surgeries involving the use of other conduits (left internal mammary artery, 95.1%; right internal mammary artery, 93.8%; gastroepiploic artery, 93.1%; and saphenous vein, 98.2%). Follow-up was completed for all hospital survivors with a mean follow-up time of 1.4 +/- 0.3 years. There were no cardiac deaths and 5 cardiac events, giving a cardiac event-free rate of 97.5%. In our limited follow-up, cardiac events have been well controlled. Midterm follow-up angiographic study is necessary to confirm our clinical outcome data.

Successful Management of Carotid Stenosis in a High-Risk Population at an Inner-City Hospital

This is a retrospective review of all carotid endarterectomies (CEA) (n=91) done from 1993 to 2002 at an inner-city hospital (Group I). This group was compared to a randomly selected group of patients (n=445) treated at a private hospital (Group II). The same high-volume surgeons performed CEAs at both hospitals. The majority of Group I patients (71.4%) were members of racial minority groups. They were also more likely to be younger (p<0.001), hypertensive (p<0.03), diabetic (p<0.001), and current smokers (p<0.001); have contralateral carotid artery occlusion (p=0.04); and present with stroke (p<0.001) than Group II patients. Despite this, the incidence of postoperative myocardial infarction (2.2% vs 0.2%, p=0.08), stroke (1.1% vs 1.6%, NS), and death (1.1% vs 0%, NS) was comparable between the 2 groups. Aggressive preoperative workup for occult cardiac disease in Group I revealed an incidence of 25.9% (n=15). Of these, 5 (33.3%) were found to have coronary artery disease severe enough to warrant intervention before CEA. In an inner-city population with increased medical comorbidities, more severe cerebrovascular disease, and relatively low volume of carotid surgery, the results of CEA were comparable to those in patients treated at a high-volume private hospital. The presence of high-volume surgeons, operating at the low-volume municipal hospital, may contribute to the low complication rate. Finally, aggressive preoperative cardiac workup in this underserved population revealed a meaningful incidence of occult coronary artery disease requiring intervention before CEA.

A CUSUM Analysis of Ruptured Abdominal Aortic Aneurysm Repair

Studies have investigated the role of hospital and surgeon case volume in outcome after ruptured abdominal aortic aneurysm repair (rAAA). Few have analyzed the learning curve of an individual surgeon. The purpose of this study was to analyze this learning curve in reducing morbidity and mortality after rAAA repair. Thirty-two consecutive patients who underwent rAAA repair during the initial 2.5 years of a vascular surgeon's career were reviewed retrospectively. They were divided temporally into two groups of 16 patients (groups 1 and 2). Outcome measures included mortality, postoperative myocardial infarction, stroke, and renal and respiratory failure. Perioperative variables previously associated with increased mortality were analyzed. The cumulative sum (CUSUM) method was used to analyze the learning curve with respect to published acceptable event rates and predetermined 80% alert and 95% alarm boundary lines. Groups 1 and 2 did not differ statistically in age, preoperative blood pressure, hemoglobin or creatinine. There was no difference in transfusion requirements (6.8 +/- 1.2 units vs. 6.4 +/- 1.0 units; p = 0.78), urine output (340 +/- 65 mL vs. 389 +/- 94 mL; p = 0.72) or clamp position. There was no difference in the incidence of postoperative myocardial infarction, stroke, or respiratory or renal failure. Thirty-day mortality in group 2 was 12% as compared to 50% in Group 1 (p = 0.03). On CUSUM analysis, the cumulative failure rate in group 2 progressed lower than the 80% reassurance line, indicating improved results with time. Mortality after rAAA repair decreased over time during an early period of an individual surgeon's career. The CUSUM method is a valuable tool in analyzing an individual surgeon's experience and shows promise in quality control in vascular surgery.

Chirurgie coronarienne à cœur battant et dysfonction ventriculaire gauche

We report our experience with systematic coronary revascularization on the beating heart among patients with left ventricular dysfunction as defined by a left ventricular ejection fraction ⩽40%. Between September 1996 and April 2000, 500 off-pump (OPCAB) revascularizations were performed (95% of all revascularizations for the same time frame, single surgeon). Among them, 76 patients qualified as left ventricular dysfunction and were compared to a similar cohort of 237 patients operated on with cardiopulmonary bypass (CPB) during the same time frame. Age and sex distribution, average preoperative left ventricular ejection fraction and incidence of preoperative unstable angina were the same for both groups. On average, 3.04±0.89 and 2.97±0.69 grafts/patient were made in the OPCAB and CPB groups respectively ( p= NS). Complete revascularization was achieved in 95% of the OPCAB group. Incidence of preoperative intra-aortic balloon assistance were higher in OPCAB (22% versus 9%, p=0.005) whereas postoperative need for new intra-aortic balloon assistance was higher in CPB (8% versus 0%, p=0.02). Incidence of postoperative myocardial infarction was comparable in both groups (6.5% versus 5.5%). Maximal creatinine phosphate of myocardial origin were lower in OPCAB group (beating heart: 32±52%, cardiopulmonary bypass: 45 ± 51%, p = 0.055). Operative mortality was lower in OPCAB group although it did not reach statistical significance (beating heart: 2.6% versus cardiopulmonary bypass: 4.6%, p = 0.3). Complete coronary revascularization on the beating heart can be achieved in patients with left ventricular dysfunction with excellent outcome and low operative mortality.

A controlled trial of substrate-enhanced, warm reperfusion (“hot shot”) versus simple reperfusion

Background. Modified reperfusion after aortic cross-clamping is claimed to reduce myocardial injury, thus improving postoperative myocardial performance.Methods. We measured perioperative release of creatine kinase-MB and troponin-T in 40 patients undergoing valve replacement (combined with coronary grafts in 12 cases) to determine whether infusion of a modified reperfusate before cross-clamp removal reduced myocardial injury. Patients were randomly allocated to one of two groups with minimization for age, surgeon, operation, and ventricular function. The control group received unmodified reperfusion, while the study group received a normothermic reperfusate, enhanced with glutamate and aspartate, for 5 minutes before removal of the cross-clamp. Serial determinations of troponin-T, creatine kinase-MB isoforms, and total creatine kinase-MB activity were made up to 5 days postoperatively. Requirements for inotropic support and evidence of myocardial infarction were documented.Results. Creatine kinase-MB activity, creatine kinase-MB isoforms, and troponin-T were not significantly different between the two groups. There were no differences in the incidence of postoperative myocardial infarction or in inotrope requirement.Conclusions. Our study did not demonstrate any advantage in using modified reperfusion in this group of patients.

Operative risk assessment

While operating upon the elderly, and even the very elderly, for cardiac, orthopaedic or vascular diseases is increasingly accepted, there is continued reluctance to recommend aggressive interventions for several malignancies, other than those arising in the colon [1]. Surgical resection is accepted as the only curative therapy for most solid tumours [2], but elderly subjects may be denied surgery because of their presumed higher mortality and morbidity; the situation that existed at the beginning of this century [3]. Surprisingly, reluctance to advise or to accept an operation is often unrelated to the presence of co-existing debilitating conditions or impaired functional status [4]. In the first half of this century operative mortality was high for patients ]70 years of age (19%) [5]. The increasing size of the elderly population meant a parallel increase in need for surgery in the elderly. A report in 1975 by Greenfield showed that operative mortality was halved during a 40-year period among the same age group [6]. This was the consequence of improvements in anaesthetic and surgical techniques, the availability of new drugs and optimised post-operative care. However, common clinical practice and scientific reporting continue to exclude the aged from optimal surgical treatment [7]. While the incidence of post-operative myocardial infarction and bronchopneumonia have remained unchanged among colorectal cancer patients treated before and after 1980, the mortality rate associated with these complications was dramatically reduced from 100 to 38% and from 55 to 15% (PB0.005), respectively, due to earlier diagnosis and aggressive treatment of post-operative complications [8]. A protocol of pre-operative evaluation, intra-operative haemodynamic monitoring and post-operative intensive care has been formalised for use in the elderly poor-risk subjects [9]. Mortality rates among a group of non-cancer patients \90 years old were 2.3% in elective surgery, 16% in urgent and 45% for emergency cases [1]. An Italian study on 435 patients \80 years old confirmed these figures; a significant difference was recorded between emergency and elective operations (morbidity 42 vs. 20%, mortality 18 vs. 6%) [2]. In a selected series of colorectal cancer patients there was a 2-fold increase in mortality in patients aged between 69 and 74 years and a 4-fold increase in those \74 years old operated on emergency basis and also operative deaths were significantly increased after emergency surgery (26 vs. 11.6%) [9]. Age-related changes are most evident under physical/ psychological stress and elderly people are slower to react and recover [10]. While anaesthesiological guidelines for management (pre-operative evaluation, intraoperative monitoring and post-operative intensive care) of elderly people at high risk for surgery are to be further developed [11,8], detailed evaluation of major organ function helps in choosing anaesthetic and pharmacological agents. Despite this wide experience, only two risk factors for peri-operative cardiac morbidity have been definitively identified: recent myocardial infarction and current congestive heart failure [12]. In the past years, multivariate analyses have identified combinations of risk factors allowing the organisation of scoring systems [13]. These scores are generally based on costly clinical and laboratory tests, often referring to further investigations. Most recently it has been argued that routine clinical evaluation before surgery is neither sufficiently sensitive nor specific and that higher costs are justified if specialised testing provides otherwise unavailable information. The topic of pre-operative assessment of cardiovascular patients is addressed for both, elderly and non elderly patients, by the recent overview by Mangano [14,15]. For these reasons the results of retrospective evaluation of large surgical series aimed at the * Corresponding author. MultiMedica 300, via Milanese, Sesto S. Giovanni, 20099 Milan, Italy. Tel.: +39 2 24209481; fax: +39 2 224209313.

Propofol and Early Extubation After Cardiac Surgery

In Response: We appreciate the concerns of Dr. Chaney regarding our recent paper on propofol-based anesthesia for cardiac surgery. His main concern relates to our trial design, whereby each group was given a different amount of fentanyl (and midazolam). We chose our groups carefully, after considering the published information about propofol. For most cardiac surgical patients, a large-dose opioid technique is rapidly becoming redundant and is being replaced with a balanced technique consisting of less opioid supplemented with benzodiazepine and/or volatile anesthetic. Many authors have shown that patients with good left ventricle (LV) function can be managed with a standard noncardiac anesthetic consisting of small doses of opioid (e.g., fentanyl, 5-15 micro g/kg). At our institution, as in many others, we have an increasing number of patients with LV impairment for whom higher concentrations of a volatile anesthetic would be inappropriate and so have opted for moderate doses of opioid, with smaller concentrations of volatile agent. This was the basis of our comparator group. If we had used less fentanyl in this group, we would have had to use more enflurane; we believe this would not have been tolerated in those patients with impaired LV function. Alternatively, if we had used less fentanyl, we would have placed our patients at risk of intraoperative awareness, a problem confronted by several recent authors. In our study, we had no cases of awareness. In fact, we have not had any cases of awareness using a propofol-based technique in more than 1800 subsequent cases (with all our patients being interviewed postoperatively as part of an ongoing quality assurance program). Our resultant extubation times (9.1 vs 12.3 h) were derived from all recruited patients: we did not exclude those who were extubated after 24 h. As stated in our article, many patients could have been extubated earlier (we, like many authors, have been victims of the intensive care unit relearning curve), and so further improvements can be expected. Our proposed technique can be fine-tuned to allow earlier extubation of most patients (note that 40% of the propofol group were extubated within 6 h). We now extubate nearly all cases within 2-8 h. We were also able to demonstrate that a propofol-based technique provided stable hemodynamics, minimum myocardial ischemia and a very low incidence of postoperative myocardial infarction (<2%). Paul S. Myles, MPH, MD, FANZCA John Moloney, FANZCA Department of Anaesthesia & Pain Management; Alfred Hospital; Melbourne, Australia

Cardiopulmonary Bypass Temperature Does Not Affect Postoperative Euthyroid Sick Syndrome?

To determine if temperature during cardiopulmonary bypass (CPB) has an effect on perioperative and postoperative thyroid function. Prospective study comparing thyroid function during and after hypothermic and normothermic CPB. Cardiac surgical unit at a university-affiliated hospital. Twelve patients scheduled to undergo cardiac operations with normothermic (n = 6) or hypothermic (n = 6) CPB. Blood was analyzed for serum concentration of total thyroxine (TT4), total triiodothyronine (TT3), free T3 (fT3), reverse T3 (rT3), and thyroid stimulating hormone (TSH) preoperatively, 60 min after CPB was initiated, 30 min after discontinuing CPB, and on postoperative days (POD) 1, 3, and 5. Patients who underwent either cold (26 degrees +/- 5 degrees C) or warm (35 degrees +/- 1 degree C) CPB were comparable with regard to age, body weight, duration of CPB, cross-clamp time, use of inotropes, total heparin dose, and length of hospital stay. Incidence of postoperative myocardial infarction, congestive heart failure, and death were similar. In both groups, TT4 and TT3 were reduced below baseline values beginning with CPB and persisting for up to 5 days after CPB (p < 0.05), free T3 was reduced for up to 3 days after CPB (p < 0.05), mean serum rT3 was elevated on POD 1 and POD 3 (p < 0.05), and TSH remained unchanged. The results of this study suggest that normothermic CPB does not prevent the development of the "euthyroid sick syndrome" during and after CPB. Despite these changes in thyroid function, most patients in both groups had a normal postoperative recovery.